Smoking tobacco product and method of making the same



United States Patent 3,111,127 SMOKING TOBACCQ PRODUCT AND METHQD OFMAKING THE SAME Charles H. .larboe, Louisville, Ky., assignor to BrownWilliamson Tobacco Corporation, Louisville, Ky, a corporation ofDelaware No Drawing. Filed June 27, 1961, Ser. No. 119,779 19 Claims.(Cl. 131l7) This invention relates to an improved smoking tobaccoproduct having improved smoking flavor characteristics and to the methodof making the improved smoking tobacoo product.

The use of natural and synthetic menthol in smoking tobacco,particularly in cigarettes, to impart its characteristic cooling flavorand aroma thereto is of increasing significance to the tobacco productsindustry. Unfortunately, there are several difficulties anddisadvantages associated with the use of menthol. Thus, due to itsvolatility, the manufacturing rooms of a tobacco products factory andalso the unmentholated tobacco products are frequently contaminated bymenthol and also considerable quantities of menthol are lost during themanufacturing process and the resulting menthol containing tobaccoproducts also have a relatively short shelf life. Also, in the smokingof a menthylated tobacco product the menthol is frequently releasedunevenly into the smoke stream.

It is a primary object of the present invention to overcome thedifficulties and disadvantages heretofore encountered and to provide animproved tobacco product and method of making the product wherein thetobacco product incorporates a menthol-containing additive imparting adesirable and pleasant cooling flavor and aroma which substantiallyeliminates the pnoblem of contamination of the manufacturing rooms andunrnentholated products in which the tobacco product has a protractedshelf life and in which the additive or its desirable menthol componentis released into the smoke stream on smoking of the tobacco product in asatisfactory regulated manner.

My invention contemplates incorporating in smoking tobacco or in asmoking tobacco product a mono ester of synthetic or natural menthol anda saturated or unsaturated aliphatic or aromatic or heteroaromaticpolycarboxylic acid or a substituted analogue of such an acid. In thecase of saturated or unsaturated aliphatic mono menthyl esters I preferemploying as acid components compounds with two carboxyl groups in thecis arrangement on adjacent carbon atoms or substituted 1, 3 in relationto one another. In the case of aromatic or heteroanomatic dicarboxylicacids, the l, 3 substitution includes only the homo dicarboxylates suchas homophthalic acid and .homoquinolinic acid.

Specific examples of the polycarboxylic acids which may be used as theacid components of the ester are butanedioic (succinic) acid;cis-butenedioic (maleic) acid; pentanedioic (glutaric) acid;cis-pentenedioc (glutaconic) acid; phthalic acid; campho-ric acid;cis-cyclohexene-LZ- dicarboxylic acid;cis-4-cyclohexene-l,2-dicarboxylic acid; homophthalic acid;homoquinolinic acid; 2,3-dimethylsuccinic acid; 2,2-dimethylsuccinicacid; 1,2,3-benzenetricarboxylic acid (hemirnellitic acid);methylsuccinic acid; itaco-nic acid; aconitic acid;cis-cyclopropane-l,Z-dicarboxylate; malic acid.

As the menthol component I may employ l-menthol, dmenthol and racernaticmenthol. Specific examples of "ice the mono menthyl esters ofpolycarboxylic acids which may be used as tobacco pnoducts additives inaccordance with my invention are mono menthylmaleate, monomenthylsuccinate; mono menthylphthalate; mono meuthyl-Z- methyl-maleate;mono menthyl-3-methylmaleate; a-menthylcamphorate; cismono-menthylcyclohexene-1,2-dicarboxylate;cis-1-meuthyl-4-cyclohexene-1,2-dicarboxylate;nronornenthylhomophthalate; mono menthylhomoquinolate; mono menthyl-mesodimethylsuccinate; mono menthyl 04,04 dimethy-lsuccinate; 2menthylhemimellitate; mono menthyl-methylsuccinate; monomenthylaoonitate; mono menthylitaconate; monomonthyl-cis-cyclopropanedicarboxylate; mono menthylmalate; cis-monomenthylglutaconate.

The mono menthyl esters that have been found to improve the flavoringcharacteristics when incorporated in a tobacco product may becharacterized by the formula:

OOOR

oo o H) ..-1 in which R is the menthyl radical and R is a mate-rialselected from the group consisting of saturated and on saturatedaliphatic and aromatic and heteroaromatic polycarboxylic acid radicalsand substituted analogues thereof and n is the total number of carboxylgroups in the acid from which the ester is derived.

The mono menthyl esters may be prepared in any desired fashion. Thus,the dicarboxylic acid anhydride may be reacted directly with menthol andthe mono menthyl ester can then be recrystallized from a suit-ablesolvent. If preferred, menthol may be added as a suspension to anaqueous solution of the polycarboxylic acid and after heating andthereafter cooling the resultant crystals are filtered from thesuspension and washed and dried.

Specific examples of the preparation of a suitable mono menthyl ester ofa polycarboxylic acid which may be used as a tobacco product additive inaccordance with my invention are as follows:

Example I Twenty grams of maleic anhydride are melted in a 50 cc.three-neck flask kept at C. with a water bath. To the continuouslystirred maleic anhydride, 31.2 grams of menthol are slowly added and themixture is allowed to react at 80 C. for eight hours. At this stage, thereaction mixture has a melting point of approximately 70 C. The monomenthylmaloate can be separated from the mixture by cooling it andrecrystallizing it from a suitable solvent such as the mixturecommercially known as Ske-llysolve B, which is essentially n-hexane.Approximately 44 grams (approximately 87% of the reaction materials) ofmono menthylmaleate is obtained having a melting point between 83-85 C.

Example 11 Approximately 16 grams of menthol are dissolved in 20milliliters of anhydrous toluene. This mixture is added dropwise, over aperiod of 1 hour, to a stirred and refluxing solution of approximately10 grams maleic an hydride in 25 milliliters of anhydrous toluenecontaining 0.01 gram of p-tol-uenesulfonic acid. After 12 hours atreflux the mixture is cooled to room temperature and extracted withmilliliters of distilled Water to remove 3 the p-toluene sulfonic acidand any unreacted maleic anhydride. The toluene is removed by flashevaporation at room temperature and the product recrystallized as above,yielding 16.1 g. (67.8%) of mono menthylmaleate, It'll. 83-85 C.

Example III Approximately 392 g. of diamenthylmaleate are dissolved in500 milliliters of p-dioxane and brought to 100 C. on a steam bath. Tothis stirred solution is added, over a three-hour period, approximately40 grams of sodium hydroxide dissolved in 200 milliliters of water.After an additional six hours the reaction mixture is diluted with 1liter of Water, cooled to C. and filtered to remove the menthol formedon hydrolysis. The supernatant liquid is acidified to a pH of 2 with 12Normal sulfuric acid, cooled to 5 C. and filtered. The semi-crystallineprecipitate of mono .menthylmaleate is recrystallized as above, yieldingapproximately 200 grams (78.9%) of mono menthylmaleate, MP. 8485 C.

Example I V Approximately 15.6 grams of menthol were dissolved inmilliliters of anhydrous chloroform and added dropwise, over athree-hour period, to a stirred refluxing solution of 10 gnams offreshly prepared succinic anhydride in milliliters of anhydrouschloroform. On cooling mono me-nthylsuccinate precipitates, M1. 5 359 C.in yield (11.9 grams).

Example V Approximately 7.8 grams of menthol are dissolved in 20milliliters of anhydrous toluene and added dropwise, over athirty-minute period to a refluxing solution of 5 grams of succinicanhydride in 25 milliliters of toluene containing 0.1 gram ofp-toluenesulfonic acid. The mixture was refluxed an additional 4 hours.After cooling to room temperature the mixture was extracted with three25 milliliter fractions of Water to remove the p-toluenesul-fonic acidcatalyst. The toluene was evaporated from the crude product at roomtemperature by flash evaporation. The mono menthylsuccinate isrecrystallized from n-hexane at 20 C. producing approximately 23.6 g. orsubstantially quantitative yields of mono rnenthylsuccinate, Ml Sit-59C.

Example VI Approximately 15.6 grams of menthol are dissolved in 20milliliters of anhydrous xylene. This mixture is added dropwise, over aperiod of 1 hour to a stirred and refluxing solution of approximately24.6 grams of 1,2,3-benzenetricarboxyllc acid (hemimellitic acid) in 25milliliters of anhydrous commercial xylene mixture containing 0.01 gramof p-toluenesulfon ic acid. After 12 hours at reflux the mixture iscooled to room temperature and extracted with 100 milliliters ofdistilled Water to remove the ptoluenesulfonic acid catalyst. The xyleneis removed by flash evaporation at 80 C. and the product monomenthylheinimellitate obtained as above.

It should be understood that in the Examples 1 to V1 set forth above anyof the other indicated polycarboxylic organic acids may be substitutedfor the acids indicated in the examples and the proportions adjusted inaccordance with the molecular weight thereof. The mono menthy-l estersmay be incorporated in the tobacco product either alone or in mixturewith each other or mixed with menthol. The proportion of the monomenthy-l ester incorporated in the tobacco product may be widely variedin accordance with taste, but I have found that satisfactory results areobtained if the proportion by weight on a dry basis is between 0.01 and1.0% of the mono ester to the smoking tobacco. Where menthol is mixedwith the ester, the proportion by weight on a dry basis may be reducedto as little as 0.005% of the combined ester and menthol to the smokingtobacco.

Any convenient method for incorporating re mono rnenthyl ester in thetobacco product may be employed. Thus, the ester may be dissolved in asuitable solvent and either sprayed on the cured, cased and blendedtobacco or the tobacco dipped therein. Alternatively, an aqueoussuspension of the mono ester may be prepared which, in turn, may besprayed on the cured, blended and cased tobacco or the tobacco dippedtherein. Under certain circumstances, a solution or aqueous suspensionof the mono menthyl ester may be applied by a suitable applicator to thepaper or leaf Wrapper for the smoking product.

Specific examples of methods of incorporating the mono menthyl ester ina tobacco product are as follows:

Example VII Approximately 100.5 grams of mono menthylmaleate isdissolved in 500 cc. of an absolute ethanol and the solution is sprayedon approximately 30 pounds of cured, cased and blended commercialtobacco. The tobacco so treated is manufactured into cigarettes usingnormal factory procedures and equipment.

Example VIII Approximately 100.5 grams of mono menthy-lmaleate is mixedwith 500 cc. of water and the resultant suspension is homogenized andsprayed on approximately 30 pounds of cured, cased and blendedcommercial tobacco. The tobacco so treated is manufactured intocigarettes using normal factory procedures and equipment.

Example IX Approximately 227 grams of mono menthylm-aleate is dissolvedin 1520 cc. of ethanol and the solution sprayed, in conjunction withother flavoring matter, onto 200 pounds of cured, cased, blended andshredded commercial tobacco. The tobacco mixture so treated ismanufactured into cigarettes using the procedures and equipment normalto conventional manufacture.

Example X Approximately 276 grams of mono menthylmaleate and 57 grams ofeither natural or synthetic menthol is dissolved in 1520 cc. of 95%ethanol and the solution sprayed, in conjunction with other flavoringmatter, onto 200 pounds of cured, cased, blended and shredded commercialtobacco. The tobacco mixture so treated is manufactured into cigarettesusing the procedures and equipment normal to conventional manufacture.

Example XI Example XII Approximately 100.6 grams of monomenthylsuccinate are dissolved in 500 cc. of absolute ethanol and thesolution sprayed on approximately 30 pounds of cured, cased and blendedcommercial tobacco. The tobacco treated in this fashion is manufacturedinto cigarettes using normal factory procedures and equipment.

Example XIII Approximately 119.5 grams of mono menthylphthalate aredissolved in 500 cc. of absolute ethanol and the solution sprayed onapproximately 30 pounds of cured, cased and blended commercial tobacco.The tobacco treated in this fashion is manufactured into cigarettesusing normal factory procedures and equipment.

Example XIV Approximately 136.8 grams of mono menthylhemimellitate aredissolved in 500 cc. of absolute ethanol and the solution sprayed onapproximately 30 pounds of cured, cased and blended commercial tobacco.The tobacco treated in this fashion is manufactured into cigarettesusing normal factory procedures and equipment.

Example XV Approximately 105.3 grams of mono menthyl-3-methylmaleate aredissolved in 500 cc. of absolute ethanol and the solution sprayed onapproximately 30 pounds of cured, cased and blended commercial tobacco.The tobacco treated in this fashion is manufactured into cigarettesusing normal factory procedures and equipment.

Example XVI Approximately 133.6 grams of mono me-nthylcamphorate aredissolved in 500 cc. of absolute ethanol and the solution sprayed onapproximately 30 pounds of cured, cased and blended commercial tobacco.The tobacco treated in this fashion is manufactured into cigarettesusing normal factory procedures and equipment.

Tobacco products made in accordance with the specific examples givenherein have been evaluated and the products were observed to burn slowerat smolder than a comparable control, to have increased firmness and torequire more puffs under a controlled smoking regime and, when testedorganoleptically, the smoking products were found to deliver smokehaving a pleasing and cooling taste and aroma characteristic of mentholat an apparently increasing rate when the ester alone was used and at anapparently constant rate when menthol was mixed with the ester.

Modifications may be made in the described embodiments of my inventionand in the illustrated examples without departing from the scope of theinvention set forth in the accompanying claims.

I claim:

1. A smoking tobacco product having improved smoking flavorcharacteristics comprising a smoking tobacco having incorporated thereina material selected from the group consisting of mono menthylmaleate,mono menthylsuccinate; mono menthylphthalate; monomenthyl-Z-methylmaleate; mono menthyl-3-methylmaleate; monomenthylcamphorate; cis-mono menthylcyclohexene 1,2 dicarboxylate;cis-l-menthyl-4-cyclohexene-1,2-dicarboxylate; mono menthylhomophthalate; mono menthylhomoquinolate; mono menthyl mesodimethylsuccinate; mono menthyl-a,a-dimethylsuccinate; monomenthy-lhemimellitate; mono menthylmethylsuccinate; monomenthylaconitate; mono menthylitaconate; monomenthyl-cis-cyclopropanedicarboxylate and mono menthylmalate; cis-monomenthylglutaconate.

2. A smoking tobacco product having improved smoking flavorcharacteristics comprising a smoking tobacco having incorporated thereinmono menthylmaleate.

3. A smoking tobacco product having improved smoking flavorcharacteristics comprising a smoking tobacco having incorporated thereinmono menthylsuccinate.

4. A smoking tobacco product having improved smoking flavorcharacteristics comprising a smoking tobacco having incorporated thereinmono menthylphthalate.

5. A smoking tobacco product having improved smoking flavorcharacteristics comprising a smoking tobacco having incorporated thereinmono mentlxyl-Zmrethylmaleate.

6. A smoking tobacco product having improved smoking flavorcharacteristics comprising a smoking tobacco having incorporated thereinmono menthyi-3-methylmaleate.

7. A smoking tobacco product having improved smoking flavorcharacteristics comprising a smoking tobacco having incorporated thereinmono menthylhemimellitate.

8. The method of imparting improved smoking flavor characteristics to atobacco product which comprises incorporating in smoking tobacco amaterial selected from the group consisting of mono menthylnialeate,mono menthylsuccinate; mono methylphthalate; mono ment-hyl-Z-methylmaleate; mono menthyl-S-methylmaleate; mono menthylcamphorate; cismono menthylcyclohexene-1,2- dicarboxylate;cis-1-menthyl-4-cyclohexene-1,Z-dicarboxylate; monomenthylhomophthal-ate; mono menthylhomoquinolate; monomenthyl-meso-dimethylsuccinate; mono menthyl-a,a-dimenthylsuccinate;mono tmenthylhemimellitate; mono menthylmethylsuccinate; monomenthylaconitate; mono menthylitaconate; monomenthyl-cis-cyclopropanedicarboxylate; mono menthylmalate and cis-monomenthylglutaconate.

9. The method of imparting improved smoking flavor characteristics to .atobacco product which comprises incorporating in smoking tobacco monornenthylmale ate.

10. The method of imparting improved smoking flavor characteristics to atobacco product which comprises incorporating in smoking tobacco monomenthylsuccinate.

11. The method of imparting improved smoking flavor characteristics to atobacco product which comprises incorporating in smoking tobacco monomenthylphthalate.

12. The method of imparting improved smoking flavor characteristics to atobacco product which comprises incorporating in smoking tobaccomono-menthyl-Z-methylmaleate.

13. The method of imparting improved smoking flavor characteristics to atobacco product which comprises incorporating in smoking tobacco monomenthyl-3-methylmaleate.

14. The method of imparting improved smoking flavor characteristics to atobacco product which comprises incorporating in smoking tobaccomono-menthylcamphorate.

15. The method of imparting improved smoking flavor characteristics to atobacco product which comprises incorporating in smoking tobacco monomenthylhemimellitate.

16. A smoking tobacco product having improved smoking flavorcharacteristics comprising a smoking tobacco having incorporated thereinbetween 0.01 and 1% by weight of a mono menthyl ester of apolycarboxylic acid.

17. A smoking tobacco product having improved smoking flavorcharacteristics comprising a smoking tobacco having incorporated thereinbetween 0.01 and 1% by Weight of a mono menthyl ester of apolycarboxylic acid having the formula:

COOR

in which R is the menthyl radical and R is a material selected from thegroup consisting of saturated and unsaturated aliphatic and aromatic andhetero-aromatic polycarboxylic acid radicals and n is the total numberof carboxyl groups in the acid from which the ester is derived.

18. The method of imparting improved smoking flavor characteristics to asmoking tobacco product which comprises incoporating in smoking tobaccobetween 0.01 and 1% by weight of a mono menthyl ester of apolycarboxylic acid.

19. The method of imparting improved smoking flavor characteristics to asmoking tobacco product which comprises incorporating in smoking tobaccobetween 0.01 and 1% by weight of a mono menthyl ester of apolycarboxylic acid having the formula:

COOR

in which R is the menthyl radical and R is a material selected from thegroup consisting of saturated and un saturated aliphatic and aromaticand heteroaromatic poly- F? s. carboxylic acid radicals and n is thetotal number of carboxyl groups in the acid from which the ester isderived.

References Cited'in the file of this patent UNITED STATES PATENTS1,673,216 Vuccino June 12, 1928 2,822,306 Thienmann et a1. Feb. 4, 19522,921,089 Hagenmeyer et a1 Jan. 12, 1960 w 2,936,320 Benoit May 10, 19602,941,907 Tousignant June 21, 1960 FOREIGN PATENTS 1,065,767 GermanySept. 17, 1959 12,736 Great Britain 1896 OTHER REFERENCES D. L. Tabern:Chemical Abstracts, 1941, 5136.

1. A SMOKING TOBACCO PRODUCT HAVING IMPROVED SMOKING FLAVORCHARACTERISTICS COMPRISING A SMOKING TOBACCO HAVING INCORPORATED THEREINA MATERIAL SELECTED FROM THE GROUP CONSISTING OF MONO MENTHYLMALEATE,MONO MENTHYLSUCCINATE; MONO MENTHYLPHTHALATE; MONOMENTHYL-2-METHYLMALEATE; MONO MENTHYL-3-METHYLMALEATE; MONOMENTHYLCAMPHORATE; CIS-MONOMETHYLCYLOHEXENE - 1,2 - DICARBOXYLATE;CIS-1-MENTHYL-4-CYCLOHEXENE-1,2-DICARBOXYLATE; MONOMENTHYLHOMOPHTHALATE; MONO MENTHYLHOMOQUINOLATE; MONO MENTHYL - MESO -DIMETHYLSUCCINATE; MONO MENTHYL-A,A-DIMETHYLSUCCINATE; MONOMENTHYLHEMIMELLITATE; MONO MENTHYLMETHYLSUCCINATE; MONOMENTHYLACONITATE; MONO MENTHYLITACONATE; MONOMENTHYL-CIS-CYCLOPROPANEDICARBOXYLATE AND MONO MENTHYLMALATE; CIS-MONOMENTHYLGLUTACONATE.